1. Field of the Invention
This invention relates to internal combustion engines and the like and, more particularly, but not by way of limitation, to a sectional intake manifold which permits increased access to intake runners, plenum, and vanes. The present invention also relates to a method for converting conventional intake manifolds to the sectional intake manifold according to the present invention.
The present invention also relates to a sectional exhaust manifold which permits increased access to runners, plenum, and dividers and, further, to a method for converting conventional exhaust manifolds to the sectional exhaust manifold according to the present invention.
2. Discussion
It is known in the art relating to internal combustion engines to provide an intake manifold having intake runners with openings through which a fuel-and-air mixture flows from the carburetor to the combustion chambers. It has been previously recognized that an air intake system designed for free breathing and maximum air flow increases high speed performance and combustion efficiency. A known method for increasing air flow through the air intake system, including the air intake manifold, is to modify the configuration of the intake manifold by reshaping or recontouring the interior walls of the intake runners, the plenum, and the vanes to reduce pressure drop and increase air velocity through the air inlets. Modification of the air intake runners is normally accomplished by removing metal from the interior walls of the air inlets.
Fuel injected internal combustion engines do not have carburetors. Fuel is typically injected either into the intake runners of the intake manifold or directly into the cylinder heads. Yet a similar benefit is obtained by reshaping or recontouring the interior walls of the intake runners, the plenum, and the vanes to reduce pressure drop and increase air flow through the intake manifold. Modification of the air intake runners is normally accomplished by removing metal from the interior walls of the air inlets. The amount of air available for combustion in the combustion chambers is the limitation on performance and efficiency. Thus, any improvement in air flow results in increased performance and increased efficiency.
Although the reason for the improvement produced by modification of the air intake runners is not fully understood, it is believed that the reshaping and recontouring of the interior walls of the air intake runners reduces the thickness of the boundary layer along the interior walls. With a thinner boundary layer, the flow of air through the air intake runners to the combustion chamber would be closer to the interior walls and act to follow the interior walls in laminar flow, thus enhancing flow of air through the air intake runners and into the combustion chamber.
Traditional air intake manifolds include cast aluminum intake manifolds and sheet metal manifolds. With cast aluminum intake manifolds, in particular, it is difficult to obtain access through the carburetor flange to the interior walls to perform the reshaping and recontouring which produces increased air flow to the combustion chambers. Restricted access to the plenum area limits the methods and tools which can be used. Maximum increase in air flow frequently results from reshaping and recontouring the interior walls of the air intake runners most remote from the carburetor flange.
It is further known in the art relating to internal combustion engines that a reduction in exhaust back pressure improves performance of the engine. Just as an air intake system designed for free breathing and maximum air flow increases high speed performance and combustion efficiency, an exhaust outlet system designed for maximum flow of exhaust gases also increases high speed performance and combustion efficiency. A known method for increasing flow of exhaust gases through the exhaust outlet system is to modify the configuration of the exhaust gas outlets by reshaping or recontouring the interior walls of the exhaust gas outlets to reduce exhaust back pressure and increase flow of exhaust gases through the exhaust gas outlets. Modification is normally accomplished by removing metal from the interior walls of the exhaust gas outlets.
As in the case of the intake manifolds, restricted access to exhaust manifold runners, plenum chambers, and dividers limits the extent to which metal can be removed from the interior walls of the exhaust manifold to reshape and recontour the interior walls of the exhaust manifold and reduce exhaust back pressure.
It is also well known in the art relating to internal combustion engines that the conventional intake manifold must be removed to gain access to the lifter valley to change or repair lifters. On most engines, the distributor must first be removed so the intake manifold can be removed. With a front-back sectional manifold, only the front section of the manifold must be removed to gain access to the lifter valley, leaving the back section of the intake manifold and the distributor in place. Leaving the distributor in place means the timing does not have to be reset. Further, although the distributor must also be removed, removal and replacement of the camshaft is permitted by removal of only the front section of the front-back sectional intake manifold, thereby reducing the time and labor to replace the camshaft.
The sectional intake manifold of the present invention permits increased access to permit reshaping and recontouring of intake manifold interior surfaces. A sectional exhaust manifold permits increased access to permit reshaping and recontouring of exhaust manifold interior surfaces.
The present invention provides a method and apparatus for achieving increased air flow through the intake and exhaust manifolds of an internal combustion engine. A sectional intake manifold includes a flanged first intake manifold section having and a flanged second intake manifold section. Bolts extend through unthreaded bores in the first intake manifold section flange into the threaded bores in the second intake manifold section flange. A seal is provided between said first section mating flange and said second section mating flange. A method is provided for converting a conventional intake manifold to a sectional intake manifold.
An object of the present invention is to provide a sectional intake manifold which permits greater access for reshaping and recontouring the interiors of the intake manifold runners, plenum chambers, and vanes.
Yet another object of the present invention is to provide a sectional intake manifold which permits access to the engine lifter valley by removing the front section without removal of the distributor, therefore leaving ignition timing unaffected.